I'm not a neander woodworker, preferring power tools for most of my woodworking, so my workbenches tend to get made from soft woods, usually construction grade spf. The tops are 1 X 8 or whatever width looks the best coming off the pile at the yard. For the tops, I use 1/4" tempered MDF, attached with a flat head screw in each corner and sometimes in the center front and back. For the glue-up bench I'll put a couple of coats of poly on it. The rest I don't put anything on them. When the tops get rough looking or broken, I just replace them. Hardly any effort at all and my bench is like new again. I once came across a new solid wood 38 X 112" X 2" thick flat surface commercial door at a Habitat Store for $40 and brought it home. I trimmed it to 32" width to remove the door handle hole and used it for the top of my new workbench. What a solid top that it made. When I moved, I left it behind, as I had no shop at the new house until I built one 2 years later. I'm still regretting that decision. Since the door skins were rosewood, I used tempered MDF to protect the top surface, since it was "just too nice" to scratch and dent up. Used carpet tape to hold the MDF on. What an unbelievably solid bench that door made.
Charley